Sweet & Savory Roasted Balsamic Onions (Low-Carb Option)
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These Roasted Balsamic Onions are the perfect sweet and savory mix, a simply gorgeous colorful side dish that's surprisingly easy to make and melt-in-your-mouth delicious.
The onions turn out surprisingly buttery soft with a fantasic flavor that compliments any meal.

If you've never tried roasted onions, after trying this recipe you'll wonder why it took you so long.
I tried it the first time because I overbought bulk organic red onions from Azure Standard (I have a problem overbuying when there's a great sale) and needed to figure out something to do with all of those onions, but I wished I'd tried it sooner!
Why You'll Love This Recipe
This recipe just has so much going for it. It's
- easy
- healthy
- customizable to be low-carb if needed.
- pretty, especially when using red onions.
- special enough for entertaining, yet easy enough for every day.
- frugal. While balsamic isn't super cheap, most of the ingredients are quite affordable.
- delicious. So good, in fact, that when I first made these, our youngest (he was very young at the time), danced around saying that this was the best dish I'd ever made!
Ingredients
Following is the basic ingredient list. For the full list with amounts, simply scroll to the printable recipe card.
- onions (red or white)
- balsamic vinegar
- oil (avocado or olive)
- paprika
- sweetener
- salt
Directions
This dish is easy peasy. Here are the basic directions. For the complete instructions, scroll to the printable recipe card.
- Simply wash the onions and cut them in half, leaving the peels on and place in a bowl.
- Combine the rest of the ingredients and pour them over the onion halves.
- Arrange the onions in a baking dish and bake.

How to Serve These Baked Onions
These onions are great on their own, but there are many other ways to use them.
- topping for main dishes like steak, chicken, turkey, or fish
- salad topping
- stir in for chilis, soups, or stews
- added to casseroles like this Paleo Shepherd's Pie
Should You Bake Onions With or Without Peels?
You can make these roasted onions either way, but there are a number of reasons why leaving the peel on is better.
- Appearance: They are simply prettier baked this way.
- Easier to eat: If you bake these without the peels, the onions can turn to mush and be kind of hard to eat. With the peel on, they have a nice little “container” that holds the onion halves for you on your plate.
- Nutritional benefits: There is a lot of nutrition in onion peels (source). So it makes sense to cook onions (that are well washed) with peel on and not to toss the onion closest to the peel. Some of these nutrients will end up in the outer part of the onion and/or in the liquid that ends up in the pan. So make sure to scoop that up and drizzle it over the onions when they're done.
- Less waste: By baking the onions in their peels, you will be more likely to eat all of the onion, rather than tossing the nutritious part just below the peel.

Recipe Notes
- Cutting the onions in half so that the stem is in the center of the cut half makes for a better presentation.
- Oil choice: I recommend choosing an oil based on its smoke point, and avocado oil has a very high smoke point. Please choose your oil based on the oven temperature that you will be using.
- Sweetener Options: Although xylitol works well for low carb, organic erythritol works as well. Organic maple syrup, honey, or organic coconut sugar are great AIP options.
Special Diet Options
- AIP: For AIP, use 1/8-1/4 teaspoon of both liquid smoke and this AIP Taco Seasoning for the paprika. Use maple syrup, honey, or coconut sugar for the sweetener.
- Low-carb: Use 1 tablespoon apple cider vinegar or red wine vinegar plus 1/2 teaspoon xylitol instead of balsamic vinegar.

Balsamic Baked Onions (Low-Carb Option)
Ingredients
- 2 pounds red onions (small to medium)
- 1/4 cup avocado oil
- 1 tablespoon balsamic vinegar
- 2 teaspoons smoked paprika (regular is OK too but smoked is nicer – see Recipe Notes for AIP)
- 2 tablespoons allulose (or other sweetener, as desired)
- 1/4 teaspoon salt (or to taste)
Instructions
- Wash onions.
- Cut onions in half and place in a bowl.
- Mix other ingredients and pour over onions.
- Toss to coat.
- Place onions flat side down in a baking dish and drizzle with any remaining spice mixture.
- Bake in 450 oven for 30-40 minutes (40 makes them softer and easier to digest). Alternatively, bake at 350 for 1 hour or more to desired doneness.
- Serve with the skins on and the extra balsamic liquid either drizzled on top or offered on the side.
Notes
- Cutting the onions in half so that the stem is in the center of the cut half makes for a better presentation.
- I recommend choosing an oil based on its smoke point, and avocado oil has a very high smoke point. Please choose your oil based on the oven temperature that you will be using.
- Any sweetener can be substituted for the xylitol. Although xylitol works well for low carb, erythritol works as well. Maple syrup, honey, or coconut sugar are great AIP options.
- AIP: For AIP, use 1/8-1/4 teaspoon of both liquid smoke and this AIP Taco Seasoning for the paprika. Use maple syrup, honey, or coconut sugar for the sweetener.
- Low-carb: Use 1 tablespoon apple cider vinegar or red wine vinegar plus 1/2 teaspoon xylitol instead of balsamic vinegar.
Nutrition
Nutritional information is provided as a courtesy and is merely an approximation. Optional ingredients are not included and when there is an alternative, the primary ingredient is typically used. We cannot guarantee the accuracy of the nutritional information given for any recipe on this site. Erythritol carbs are not included in carb counts since they have been shown not to impact blood sugar. Net carbs are the total carbs minus fiber.
I hope you enjoy this recipe. It's great for an every day side dish and pretty enough for a special occasion as well.
What is your favorite recipe that uses red onions?


I haven’t tried this yet, but it sounds wonderful. What can I use instead of xylitol? I don’t have that in the house because we have dogs.
Hi there! There were some other options mentioned in the Recipe Notes and I added another option to the Recipe Card as well. Hope that helps!
Do you bake these with the flat (cut) side down or up?
You could do either but flat side down is the better way to do it so that a larger area marinates in the juices. Enjoy!
I just updated the recipe to make it more clear. Thanks for a good question!